1. Field of the Invention
The present invention relates to a data communication apparatus, an image forming apparatus management system using the data communication apparatus and a counter information transmission method therefor.
2. Description of the Related Art
As an image forming apparatus management system, a system is generally known in which image forming apparatuses such as plain paper copying machines installed in unspecified number of customers (users) and provided with remote diagnosis can connect with a central management apparatus installed in a service center (base of sales and service) or the like using a data communication apparatus (communication adapter) and a communication line such as a public circuit, and the image forming apparatuses are remotely controlled by the central management apparatus through the communication line and the data communication apparatus.
In such an image forming apparatus management system, the image forming apparatus counts (accumulates) the number of formed images according to image forming operations and is equipped with a counter that stores counter information representing the counted value.
The data communication apparatus has a connecting means that can connect a plurality of image forming apparatuses. The data communication apparatus regularly (once a day at a predetermined time, which is previously set, for example) obtains the counter information representing the value of the counter from the image forming apparatuses connected by the connecting means. Further, the data communication apparatus regularly (once a month on a predetermined closing day, which is previously set, for example) transmits maintenance contract management data to the central management apparatus through the communication lines. The maintenance contract management data include the obtained counter information and model number information of the image forming apparatus from which the counter information is obtained. The transmission is performed at intervals longer than the interval for obtaining the counter information.
In the above-mentioned data communication apparatuses, when the counter information is regularly obtained from the image forming apparatus (corresponding image forming apparatus) connected by the connecting means, actually, the obtained counter information is always provided as newest counter information (the counter information is updated by overwriting the counter information obtained at the last time). For this reason, when abnormality occurs, for example, a counter value becomes “0” or is garbled due to noise or the like in the corresponding image forming apparatus, the data communication apparatus obtains the counter information representing an abnormal counter value, stores the counter information thereof as the newest counter information, and transmits the counter information, as the maintenance contract management data, to the central management apparatus.
When such maintenance contract management data are received, the central management apparatus performs an accounting process based on the maintenance contract management data. However, an appropriate accounting process cannot be performed. Thus, it is impossible to charge a correct maintenance contract fee to a customer of the corresponding image forming apparatus.